EV171-S-00A – SMALL OFF-LINE REGULATOR EVALUATION BOARD

EV171-S-00A Rev.1.0

www.MonolithicPower.com

6

9/23/2015

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CIRCUIT DESCRIPTION

The EV171-S-00A is configured in a buck

topology to demonstrate the performance of

MP171. MP171 is a primary side controller which

provides accurate constant voltage. It simplifies

the schematic and minimizes the BOM cost.

FR1 is used to protect circuit from component

failure or some excessive short events; also it can

restrain the inrush current.

C3, L1 and C4 compose CLC filter to meet the

conducted EMI standard EN55022. C3 is also

used for energy storage and protecting against

line surge.

With FR1, C3 and C4 used, EV171-S-00A meets

2kV IEC61000-4-5 surge immunity standard.

C1 is the sample-hold capacitor used for

reflecting output voltage. R1 and R2 are resistor

divider for detecting output voltage by sampling

voltage on C1.

D3 is the freewheeling diode. For universal

voltage applications, use a diode with a 600V

reverse block voltage. Fast recovery diode or

ultra fast diode is recommended for better

efficiency and reliable operation.

C5 is the output capacitors for 5V output. R3 is

dummy load to lower the output voltage of 5V rail

at no load condition.